Flexible connection



July 12, 1966 w, J, NELSON ET AL 3,260,069

FLEXIBLE CONNECTION Filed Nov. 18, 1963 2 ywgmw United States Patent 3,260,069 FLEXIBLE CONNECTION William J. Neilson, Whittier, and Erskine P. Garrison and Lloyd L. Garner, Long Beach, Calif., assignors to Smith Industries International, Inc., Compton, Calif., a corporation of California Filed Nov. 18, 1963, Ser. No. 324,410 2 Claims. (Cl. 64-2) This invention relates to improvements in flexible connections.

A primary object of the invention is to provide a flexible connection which is highly efiicient in its ability to transmit both torque and thrust from a driving element to'a driven element.

Explanatory of the present invention, the flexible connection herein disclosed has been designed for use in the construction of a well drilling apparatus such as that disclosed in United States Letters Patent No. 2,898,087, issued August 4, 1959, to Wallace Clark, and in the well drilling apparatus disclosed in our copending application Serial No. 322,596, filed November 12, 1963. In the above mentioned patent and application a relatively stationary drill string is employed near the lower end of which there is a fluid-operated motor. This motor may be in the form of a Moyno pump having an outer stator and an inner rotor. This pump, on having circulation fluid discharged downwardly therethrough and through the drill string, functions as a fluid-operated motor and is operatively connected to a rotary well drilling bit that is rotatably mounted at the extreme lower end of the drill string. The rotary well drilling bit rotates about an axis which is stationary in relation to the drill string but the lower end of the rotor of the fluid-operated motor (pump) moves in a gyratory path in relation to the drill string. Consequently some form of flexible connection must be provided between the gyrating lower end of the rotor and the well drilling bit which rotates about a stationary axis which will transmit torque from the rotor to the well drilling bit to forcibly rotate the well drilling bit. Such a connection must not only be flexible and capable of transmitting torque but also should be capable of transmitting thrust so that the rotor will not be expelled by the circulation fluid from its stator. This is one illustration of the type of flexible connection with which the present invention is concerned but the present invention is not restricted thereto. On the contrary, it may be employed in any situ ation where it is desirable or necessary to be able to transmit flexibly torques of great magnitude and thrusts of great magnitude.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

FIGURE 1 is a view in side elevation of the flexible connection embodying the present invention, part of the external cover being broken away and shown in vertical section.

FIG. 2 is a vertical section taken substantially upon the line 22 upon FIG. 1 in the direction indicated.

FIGS. 3 and 4 are horizontal sections taken substantially upon the lines 33 and 44, respectively, on FIG. 2.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, the flexible connection embodying the present invention consists of upper and lower connectors and 11 shown as being externally threaded members by which they may be respectively connected to driving and driven elements. Thus the upper connector 10 may be connected ice to the rotor of a fluid-operated motor and the lower connector 11 may be connected to a rotary well drilling bit. Between the two connectors 10 and 11 there is a tubular member, generally indicated at 12, which is transversely divided into a plurality of segments having mutually interfitting portions which enable torque to be transmitted from each segment to its neighbor. Preferably these segments are formed by cutting a heavy walled tube with a cutting torch on tortuous paths such as those indicated at 13 and 14. In following the tortuous path each segment is, in effect, provided with lobes 15 which loosely fit between corresponding lobes on the adjacent segment. Each lobe or interfitting portion 15 is widest near its extremity than elsewhere so that although there is a clearance space 16 between each lobe and the adjacent segment, the segments of the tubular member 12 are, in effect, locked against total separation from each other. The clearance space 16 is formed by the metal that is removed from the tubular member 12 by cutting on the tortuous paths 13 and 14 and this clearance space enables the segments to assume either an aligned position with each other, as shown in FIG. 1, or positions such as is illustrated at the bottom of FIG. 2 wherein any one segment may have its axis angularly related slightly to the axis of an adjacent segment. Thus the interfitting lobes 15 on the segments together with the clearances 16 form a torque-transmitting means for transmitting torque from one connector 10 to the other connector 11 and at the same time permit of flexibility in that each segment can be angularly displaced in relation to its neighboring segments. Consequently, if the connector 10 is connected to a driving element which rotates and moves through a gyratory path and the connector 11 is connected to a driven element which rotates on a stationary axis, torque may be adequately transmitted from one segment of the tubular member 12 through neighboring segments to drive the driven element.

It is likewise desirable that the flexible connection be capable of transmitting thrust and in such a manner that thrust will not be transmitted by the lobes 15. If thrust is transmitted by the lobes 15 the clearance spaces 16 will be closed not only where required to transmit torque but also the locations required to transmit thrust and this may involve unnecessary friction which is undesirable. To this end there is disposed within the tubular member 12 between the connectors 10 and 11 a series of thrust-transmitting elements consisting of a series of balls 17 between which there are socketed members or spacers 18. The ball and socket engagement between the balls 17 and their spacers 18 permits of universal movement of the thrustcarrying members relatively to each other but carries all of the thrust between the connectors 10 and 11 due to the fact that the over-all length of the thrust-carrying members is such as to maintain the vertical clearances between the lobes 15 when the segments of the tubular member 12 are axially aligned with each other.

The tubular member 12 is preferably enclosed within an outer casing 19 the ends of which are held in place such as by hose clamps 20. In the preferred form of con struction the connectors 10 and 11 have passages therethrough indicated at 21 and 22, respectively, for the passage of lubricant. These lubricant passages, in turn, communicate with passages 23 and grooves 24 in the thrustcarrying members so that lubricant can be supplied to the engaging surfaces between the balls 17 and the socketed spacers 18 and to the clearance spaces 16.

It will be appreciated from the above described construction that the flexible connection enables torque to be adequately transmitted from the connector 10 to connector 11 and also enables thrust to be transmitted from the connector 10 to connector 11. At the same time the connection between the two connectors is quite flexible within practical limits so that if connector 10 is connected to a rotary element that moves in a gyratory path or is connected to a driving element whose axis of rotation is disaligned or displaced laterally from the axis of rotation of connector 11, both torque and thrust will be adequately transmitted. As the segments of the tubular member 12 do not undertake to transmit thrust but merely torque, friction of the connection is materially reduced.

If for any reason the driving element and the driven element to which the connectors 10 and 11 are connected should tend to separate, the interlocking of the lobes 15 with each other will prevent separation of the segment of the flexible connection.

Various changes may be made in the details of the construction without departing from the spirit and scope of the invention as defined by the appended claims.

We claim:

1. A flexible connection comprising a plurality of axially alignable tubular segments having mutually interfitting portions enabling torque to be transmitted from each segment to its neighbor, each segment being capable of having its axis angularly related to that of its neighbor and a plurality of balls and socket members disposed within the segments for transmitting thrust from one endmost segment to the other endmost segment, the balls being solid and the socket members between said balls being solid and having ball contacting opposite ends, a portion of said socket members engaging the inner wall .of an adjacent tubular segment to hold the balls along the axis of the tubular segments, another portion of each of said socket members being out of contact with the inner wall of adjacent segments, and said balls being of less diameter than the inner diameter of said tubular segments, whereby lubricant flow passage is provided exteriorly of the balls and socket members and between them and the interior walls of said tubular segments.

2. A flexible connection as defined in claim 1, wherein the flexible connection in its entirety is provided with means for maintaining it under hydrostatic pressure.

References Cited by the Examiner UNITED STATES PATENTS FRED C. MA'I'IERN, JR., Primary Examiner.

BROUGHTON G. DURHAM, Examiner.

DALE H. THIEL, Assistant Examiner. 

1. A FLEXIBLE CONNECTION COMPRISING A PLURALITY OF AXIALLY ALIGNABLE TUBULAR SEGMENTS HAVING MUTUALLY INTERFITTING PORTIONS ENABLING TORQUE TO BE TRANSMITTED FROM EACH SEGMENT TO ITS NEIGHBOR, EACH SEGMENT BEING CAPABLE OF HAVING ITS AXIS ANGULARLY RELATED TO THAT OF ITS NEIGHBOR AND A PLURALITY OF BALLS AND SOCKET MEMBERS DISPOSED WITHIN THE SEGMENTS FOR TRANSMITTING THRUST FROM ONE ENDMOST SEGMENT TO THE OTHER ENDMOST SEGMENT, THE BALLS BEING SOLID AND THE SOCKET MEMBERS BETWEEN SAID BALLS BEING SOLID AND HAVING BALL CONTACTING OPPOSITE ENDS, A PORTION OF SAID SOCKET MEMBERS ENGAGING THE INNER WALL OF AN ADJACENT TUBULAR SEGMENT TO HOLD THE BALLS ALONG THE AXIS OF THE TUBULAR SEGMENTS, ANOTHER PORTION OF EACH OF SAID 